Acrylic PSAs are utilized in many applications for bonding a flexible material to a surface, and are used, for example, in the tape and label industry due to their high solids content, low volatile organic content, good UV/thermal stability, and high coating speed. Traditional acrylic emulsions incorporate tackifier dispersions to enhance their adhesion to low energy surfaces. However, use of such tackifiers has the disadvantages of poor water resistance, yellowing, and decreased cohesive strength.
Acrylic PSAs are typically produced by emulsion or solution polymerization, with emulsion polymerization being preferred. The adhesion properties of acrylic emulsion PSAs are influenced by the type and relative amounts of the monomers employed in the polymerization process.
Accordingly, there is a need for acrylic emulsion PSAs having enhanced shear strength while maintaining good adhesion to low energy surfaces, such as polyethylene or polypropylene, without the use of a tackifier dispersion.